under no-tillage as well as running the risk of ruining his soil,
and shortening the life of his machinery. Thus, under rye
influence, the conventional-tillage forage may look profitable in
the near future, but in the long run the farmer may expose the soil
to erosion and decrease its productivity capacity for future
generations. No-tillage mulch would be the method of choice if the
farmer wished to conserve both soil and money. In order to produce
a crop under the control (fallow) the farmer would have to spend
$13.86 more to reach the sufficiency level of corn than under no-
tillage mulch.

 If the farmer could not afford any N fertilizer under rye, the
BMP would be no-tillage mulch. In this no added N situation, no-
tillage mulch has the largest leaf area (Table 6) as well as a
2.48% N concentration (Table 9), only 0.22% away from the 2.70% N
sufficiency level6. The rye is not a legume, and thus under
conventional tillage management, there is no symbiotic bacteria
converting the N to NO3 and releasing it to the soil. Thus, under
rye, the benefits of a mulch are the strongest as well as the
management treatment of no-tillage.

 As far as N concentration is concerned the farmer, under rye
cover crop, with no applied N is better off than the farmer who
adds 67 kg N/ha. This drop in average N concentration from 0 kg
N/ha to 67 kg N/ha (Table 8) can only be explained by a dilution
effect. Without the N-fixing bacteria converting N to NO3 under a
legume, corn under rye is so N starved that it only takes a little
N to "jumpstart" an explosive growth (37.1% in dry weight, Table 7)
that spreads the N throughout the new, large ear leaf which dilutes
the N concentration in the leaf. Thus, it takes a large amount of
inorganic N fertilizer under all methods to bring the N
concentration up to the sufficiency level in the newly expanded
leaf.

 Corn ear leaf areas, dry weights, and N concentrations can be
used as diagnostic tools to predict corn yield. Thus, the
assumption is made that the larger the leaf area and the heavier
the dry weight the larger the corn yield will be. The estimated
leaf areas and dry weights varied at this 2.70% N6 sufficiency for
each management scheme under each cover crop (Tables 9,10).